This invention relates to transducers. It is disclosed in the context of an electrodynamic loudspeaker, but is believed to have utility in other applications as well.
Most automotive original equipment loudspeakers have paper diaphragms. Automotive loudspeakers are almost inevitably exposed to extreme environmental conditions, such as, for example, exposure to water and to high humidity. Like most papers, the papers from which such loudspeaker diaphragms are constructed may warp when exposed to water and saturated or very humid air. Of course, warped diaphragms may perform poorly, for example, distorting the loudspeaker""s sound or causing the loudspeaker""s voice coil or voice coil former to rub against the frontplate of the loudspeaker""s magnet assembly. Waterproof and water-resistant paper diaphragms are therefore highly desirable for automotive loudspeakers.
Various attempts have been made to reduce the sensitivity of loudspeaker diaphragms to atmospheric moisture. There are, for example, the loudspeakers described in U.S. Pat. Nos.: 3,612,783; 3,780,232; 3,834,486; 3,858,680; 3,946,832; 3,997,023; 4,071,111; 4,140,203; 4,478,309; 5,008,945; 5,319,718; 5,650,105; and, 5,734,734. This listing is not intended as a representation that a thorough search of the prior art has been conducted or that no more pertinent art than that listed above exists, and no such representation should be inferred.
According to the invention, a transducer has a body having an outer region which is generally straight tapered in cross section and an inner region which is generally an arc of a circle in cross section. The inner and outer regions meet along a closed plane tangent curve. The outer region includes a decoupling region which extends around the outer region along at least one closed plane curve.
Illustratively according to the invention, the closed plane tangent curve is substantially a circle.
Alternatively according to the invention, the closed plane tangent curve is substantially an ellipse.
Further illustratively, the at least one closed plane curve is substantially a circle.
Alternatively according to the invention, the at least one closed plane curve is substantially an ellipse.
Additionally illustratively according to the invention, the decoupling region includes at least one decoupling rib which forms a closed plane curve which extends around the body.
Illustratively according to this aspect of the invention, the decoupling region includes first and second, uniformly axially spaced decoupling ribs which form first and second closed plane curves, respectively, which extend around the body.
Illustratively according to this aspect of the invention, the decoupling region includes first and second, uniformly axially spaced decoupling ribs which form first and second closed plane curves, respectively, which extend around the body.
Illustratively according to the invention, the transducer body includes bleached and unbleached fibers treated with a silicone to render the body water resistant.
Further illustratively according to the invention, the outer region terminates at an outer perimeter. A surround couples the outer perimeter to the support. The surround includes a foam.
Illustratively according to this aspect of the invention, the foam includes a polyethylene terephthalate (PET) foam.
Additionally illustratively according to the invention, the surround includes a substantially parabolic cross section substantially perpendicular to the axis.